<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div id="content">一个按钮</div>

<script>
  function f1() {
    alert(1)
  }

  document.getElementById('content').onclick = function () {
    
  }

  

</script>

</body>
</html>
